Center gage for threading tools



May 6, 1947. AQ E. BELzuNG '2,419,941

CENTER GAGE FOR THREADING [TOOLS Filed Aug. 2s, 1944 Patented May 6,1947 UNITED` STA'I'ESy PATENT OFFICE CENTER, GAGE FOR THREADING TOOLSAlexander Emil Belzung, San Diego, Calif.

Application August 23, 1944, Serial No. 550,816

3 Claims. (Cl. 33-89) (Granted under the act of March 3, 1883, asamended April 30, 1928; 370 O. G. 757) My invention relates broadly to acenter gage and more specifically to a gage by which accurate setting upof threading tools for precision threadcutting on engine lathes may beaccomplished.

It is an object of the invention to provide a gage for setting regularturning tools and cut-off tools as well as thread-cutting tools forexact centering of the tools of the respective kinds with respect to thework, and in the case of a cutting-off tool, an alignment of the latterwith the direction of the intended cut.

Another object of the invention is to provide a gage, desirably but notnecessarily ixedly embodying a spirit level by means of which the gageis leveled on the work after temporary positioning thereof on the workin a lathe, for an immediately subsequent use of the gage as a guide insetting the cutting tool whatever its type.

A further object of the invention is to provide a gage of the characterdescribed that is cheaply and easily constructed, easy to adjust andelicient in operation.

With the above and other objects in view the invention consists in theconstruction, combination and arrangement'of parts as will be describedmore iully hereinafter.

Reference is to be had to the accompanying drawings, forming a part ofthis specication, wherein like reference characters indicatecorresponding parts throughout the several views, and in which:

Fig. 1 is a top plan view of the gage applied to a piece of work,

Fig. 2` is a side elevation of the gage, the mark being shown insection,

Fig. 3 is a sectional view taken on the line 3 3 of Fig. 1, and

Fig. 4 is a sectional view taken on the line 4-4 of Fig. l.

Heretofore it has been the practice in setting a tool for cutting apiece of work in a lathe, rst to use a gage to locate the center line ofthe work so that it might be properly set up in the lathe and then touse another gage to set the cutting tool for a desired angle to cut.This dual operation has proven to be time consuming and apt to produceerrors, particularly in precision cutting of threads when practiced byapprentices. By the gage now about to be described theabove twooperations are performed by but asingle adjustment of a gage on the workwith an attending reduction of possible errors.

Referring more particularly to the drawings, 5 indicates a piece ofround work which is assumed to be gripped in the chuck of a lathe, andwith 2 respect to which a threading tool is adapted-,to be oper-ativelyset by means ofthe present invention. The center gage consists of aclamp by which it is adjustably and temporarily attached to the workwhen chucked in the lathe, a gage piate for determining the center lineYof the work and a spirit level for obtaining the proper adjustment ofthe center gage with respect to the work.

The clamp is of the usual construction, consisting of a U-rnember 6through one leg of which a screw l operates to clamp the gage 9 upon thepiece of Work between a button 8 mounted on one end of the screw, andone straight side of the gage plate which is -attached to the otherlegof the U-mernber in any desirable manner.

Twosides of the gage4 plate meet to forma right angle, while the thirdside is shaped to form one or more an-gles of dilierent degreesV withrespect to the center line ofthe plate. The left or second side which isdisposed perpendioularly to the work is used in positioning acutting-off tool. Each of the anglesof the third side is so arrangedthat a threading tool when placed against it, will be in position to cutthreads of a desired type. In the drawings this side Il of the plate isshown as having angularities of 141/2 degrees and 30 degrees,respectively to guide the operator in aligning a threading tool to cutAcme threads of 29 degrees or Standard V-threads of degrees depending onwhich of the angularities is used. Of course it will be understood thatthese particularangles are merely illustrative, a other desired anglesmay be availed of.

In order that thegage may be properly centered along the work, theforegoing one straight side l2 of the plate is provided with a V- cut ornotch extending throughout its length, more clearly seen in Fig. 3, andinto which the work is seated when the gage is applied. When the work isproperly seated in the V-notch, the gage will be ready for adjustment tothe necessary horizontal position from which the altitude setting of thethreading tool is made. To this end one of the lateral faces of the gageis recessed at I4 to establish a depressed plane surface which isprecisely in line with the center of the V-notch to aid in centering thethread cutting tool as presently explained. In cutting precision threadsit is necessary that the gage be level with the work, and to obtain thisassurance a spirit level I3 is attached to the gage in such relationshipto the plane surface of the recess I 4 as to indicate when said surfaceis horizontally disposed with reference to the center line of the work.Should it be desired to omit the attachment of the level, a separate,pocket-size level may be seated on the plane surface of the recess I4during the gage-leveling act, and then removed. But in any7 event thespirit level is essential to the use of the gage because without it theplane leveling surface of the recess could only bychancelbetbrought intohorizontal valignment Withthe axial'center of 4"the Work.

As previously stated the gage is particularly adapted for use with roundwork, although not limited to such. In use it =isi-so1placed`on1the Workthat the V-notchwill embrace the work. The uppermost plane surfaceoftherecess lzwill coincide with the plane of theiaxial center of the vwork, said surface radiatingfrom the axial center regardless of theinitial position of the gage. The gage is next levelled by the spiritlevel, after which it is tightened to the Work by the ".clamp, theuppermost surfaceiof the recess'thenstanding perfectly hcrizontalandcentered on the axis *f-fthe work. v fAssumingv-'that 'a fthreadfcutting tool has I#been 4clamped in the tool VV'post '(neither tool norpost shown) the `operator manipulates the fto'o'l postup-or down,fforwardor backward =until1the ftool lies against and parallel '5to the-fhosen angle of thesidell ,aand-thecuttin'gpoint o'flthei tool isilushwith Athe surface 1M. The 'tool ils (thenv in thecor're'ctcutting-position A and vneeds only t'o :be advanced 5in-to' contact withthe `Work VA"-'forfth'e ccmmencem'entiof the Vctustingroperation,V'preparatory'to Whichf-th'ef gage is removed.

Tft \will-fbe understood that the above fdescripftion fand accompanying-drawings comprehend only thefgeneral and :preferred `embodiment of,

the invention -and fth'a'tlvar'ious-1 changes fin details i 71.1Agagefor-aidingincentering a'thread cut- :img t'ool .witnwespecttoaheexigera-.cylindrical pier-:enfWorkfsaid*gage1comprising a plate with' a'wnotch Landfclamp means, respectively, for *temporarily receiving and'a'lxing l'the -plate'to ftheiwoligfone of tl'ie-jsideslo'f 'the:platebeing so 'fformei ;as 'fto establish "a predetermined 'angle -withrespect to 'thework'fafportion 'of rthe plate beingrecessedea'djacenttol saidonef's'ide itopro- 'vide ILa planesurf-aceflying lin the vplane -'o'f the 'centerfof'the Vnotc`h.

2. A gage for aiding in centering a thread cutting tool with respect tothe axis of a cylindrical piece of Work, said gage comprising a platehaving a contiguous pair of sides at mutual right angles, one of thesides having a V-notch longitudinally thereof to receive the Work, andmans carrie'dby the fplate atssaidfside for :temporarily aflixing theplate to the-work, aftliirdside of the plate having at least oneangularity so formed `-as to establish a predetermined angle withrespect .to the work, a portion of the plate being recessed adjacent tothe angularity to provide a 'iplanegsurfaceslying in the plane of thecenter of the V-inotch, anda level so carried by the plateandsorelatedtofthe plane surface as to indicate whenxsaid surface ishorizontally disposed with reference to the center line of the work.

f3. Agagefonaiding in centering a thread cutting tool'withrespect to theaxis of a cylindrical piece or work, said gage comprising a plate hav-Ping lateral faces-faudra contiguousipairsiof Sides :at :mutual :rightzangles, .one :of lthe :sides :having -a- Venotch longitudinally`thereof `to receive :the work, Athe 'other lside .havingwa rcavity, :aspirit 'level sequesteredrin ftheacavity :butrvisible for in- :spectionat'one ofthe 'lateralifacesyiclamprneans carriedby vthe tplateatfsaidone side for temporarily axing .the plate to the'work,said'onevlateral face being lrecessed in'fthe `plate to {provide a 'surface '.in-a plane? at -a depth l coincident with the centerfplane-,ofrthet\l'-.notch, and: a'third side of vthe 'plate Yhaving fat leastfone=angularity contiguous to .the :recesse'dzsurface for-usezirrs'etting' the zcutting pitchio'f '.the tool.

:ALEXANDER EEMIL :BELZUNG.

REFERENCES CITED The following references lare f of Yrecord in 'the illeYof this patent:

'STATES :PATENTS Number i Name Date 1,171,329 "Early Feb.l8,`1916"1,845,449 "Smith Feb. '16,. 1932 548,329 St'emmerich Oct. 22, 1895-450,457 Green Apr. .1891 625,019 Cardell Mayv 16, 1899 1:,28'4g8'79I'Donaldson "Nov. '12, l1918 115855490 Hainsworth 'May 18, 1926 FOREIGNPATENTS Number 'Country Date 8,406 British 1891

